In a conventional Downlink Control Indicator (DCI) format 1C is used to schedule Paging Channel (PCH), Random Access Channel (RACH) responses message and Broadcast Channel (BCCH) message (SIB1 and SI-x, x=2, . . . , 8). Conventionally, the following definitions are given:
Redundancy Version (RV): 0 bit long, i.e. implicit indication.
The RVs of System Information Block 1 (SIB1) are bound with a System Frame Number (SFN) and subframe numbers, and different RVs are used in an 80 ms. The RV sequence of SIB1 is RV0, RV2, RV3, and RV1. The RVs of System Information x (SI-x) are bound with an SFN and subframe numbers also.
In conventional systems, the duration of each system frame is 10 ms and system frames are numbered from 0. One system frame contains 10 subframes, numbered from 0 to 9. The relation in time sequence of system frames and subframes is shown in FIG. 1.
Within an 80-ms cycle, there are 8 system frames, in which SIB1 is transmitted on subframe numbered 5 of each system frame having an even SFN. The RV sequence of SIB1 is 0, 2, 3, 1. SI-x is transmitted within a specified transmission window, the length of which may be {1, 2, 5, 10, 20, 40} ms. Each SI-x message is transmitted with a certain number of retransmissions within the transmission window. Each retransmission is done on one subframe and the transmission window of every SI-x message is close to each other but cannot overlap. The transmission window of SI-x can overlap with the transmission window of SIB1 but an SI-x message cannot be transmitted on a subframe where SIB1 is transmitted.
In conventional systems, there is no solution for binding the RVs of SI-x with an SFN and subframe numbers and as a result, the performance of SI-x message retransmissions cannot be guaranteed. The present invention improves upon conventional systems as described below.